My Scenic II 1,6 16V doesn't start after pressing the start

Customer Question

Hi Robert,my Scenic II 1,6 16V doesn't start after pressing the start button. The alternater turns the engine, but it won't start.It came mol out of the moment.Where should I start to search. (All fuses are good, fusebox looks proper)

your persume is right. And no warning lights before it happens.It was a quite sudden problem. had a problem during the two days before to start the engine. It started "lumpy?"While I try to start (without success) i smelled fuel, like on my old bike, when it won't start.I didn't check spark, because the plugs are quite new.

I think your best step here is to see if spark is present when you spin the engine over..but first id ensure the timing belt hasnt actually broken..and east way to know that..is to take the oil cap off..and observe the cams inside..have someone spin the engine over and watch the cams spins too..if so then the belt should be fine..sometimes if the engine spins over faster than usual can be another sign of that...but as it stands id certainly check for spark..pull the coils out..and use spark plug tester or even remove one plug and stick into the end of each coil..make sure the sparkplug is grounded..and the see if you can spot it sparking..if not? then id maybe put a guess at a bad crank position sensor..but without scanning and montioring the crank sensor then your pretty much guessing..but nine times out of ten..if you have no spark..then its always due to a bad crank sensor..as they are quite common for failure..the crank sensor sits above the gearbox bellhousing..and held with 2 bolts..so if you can remove that and clean the ensir up.reinstall and then see if that helps...

thats fine...the sensor lives at the top end of the gearbox beellhousing..thats where the gearbox meets the engine..you'll need to move the air cleaner out the way to see it..at the top the connector goes straight to the sensor..the sensor sits on a curved bracket held with 2 bolts....once you see that then..remove the sensor and check the tip is clean and free of rust..as the tip is magnetic..so can pick up metal filings and prevent it working..sometimes if you plug it in depending if you use a high end scanner you can montior if the crank sensor is working or live data graph it..or you can use scope and back probe the signal wire to see if its feeding back to ecu..but of course you'll need something like a scope to do that...which id imagine you dont have...but like i say above check the sensor visually and check for spark at least and see form there..

Hi again,I checked your list as far as possible with my possibilities.1. Camshaft is rotating.2. I checked (just one) sparkplug. There is a spark when the engine is turning.3. Unmounted the crank position sensor. There was a bit of dirt/rust on the magnetic tip.I ordered a new sensor anyway. But no after seeing the spark, maybe I was a bit too fast with that.How should I continue?

Customer:replied 1 month ago.

Hi again,I checked your list as far as possible with my possibilities.1. Camshaft is rotating.2. I checked (just one) spark plug. There is a spark when the engine is turning.3. Unmounted the crank position sensor. There was a bit of dirt/rust on the magnetic tip.I ordered a new sensor anyway. But no after seeing the spark, maybe I was a bit too fast with that.How should I continue?

Customer:replied 1 month ago.

Hi Robert,i got the information from my wife, who is driving the car most of the time, that there were some random start problems aproxm. during the last 2 weeks. The car just started sometimes weak or started and turned off again. But did it in the 2nd or 3rd round then to run. So this sounds like the described problems with the TDC.I'm also thinking that it could be a problem with the immobilizer system?The red light on the dash board is blinking. When I press the start button, it is constantly on for a moment and then it turns off with the engine spinning over, but no starting.

Ok..well you'll be using the keycard ignition system? maybe try the spare keycard if thats the case to rule that out..sometimes these can be quite common problamatic when it comes to starting..for example the the card reader that you slot the keycard into has small microswitches within it that senses when the cards in,sometims these can get a build up of dust that prevents that,os hoovering out the slot can help..and of course normall practice you depress the clutch pedal fully to the floor and push start..then this will command the immobliser off and the neutral safety switch off.alowing it to start...as far the tdc sensor..goes.theres nothing wrong with trying..what you could do is if you have any easy start..try spraying that into the intake and see if it catches..if not then its means theres no spark..if it does then its fueling problem or immobiliser

Ok Robert,I changed the tdc sensor. Engine won't start. Starter spray into the intake, engine won't start.The blinking immobiliser lamp turns off when I push the ignition button and try to start.I had to take out the battery for recharging it. Could that effect some result in the starting problem?What is about the camshaft hall sensor?I don't know how to continue.

Ok..if youve sprayed easy start in the intake and it still doesnt start means its lost spark..i know you meantioned that its does have a spark..so there shouldnt be any reason why it shouldnt fire up on that..unless there is mechanical problem..timing knocked out.i suppose rather then stripping it down to see that ..you would need to scope the cam and crank sensor signal return wires..to see if they are returning signal & aligned or out of spec..that would 100% confirm if timing is correct or no.or if the sensors are working or not..i fear that might be thenext route here..rather then throw parts at it...the only way to know if the immobliser is shutting off once it see the card is by diagnostic..but it appears when you do and the light goes out.and doesnt flash means the immobliser is shut down..

Hello again,I've borrowed an iCarsoft i907 OBD2 data reader for Renault and Dacia from a friend today.Have to check it out a bit better. But what I found out alreay:Immobilizer turns off a soon as I press the start button.It also gets a signal from the TDC.Reading camshaft sensors says "stage 3" ??Some data I can't read, or didn't find out how to do, yet. It is difficult because I have to press the starter every time I want to get the data.But as you know the engine doesn't start, yet. But by going on and on I start smelling fuel, after several start procedures.I'm afraid to destroy the catalyser.

If your smelling fuel then that means the injectors are working or the fuel delivery system should be fine..it will also mean that the fuel injected isnt burning..so means you dont have spark..if you pull the spark plugs out and they are wet..then you have no spark situation..is the neutral safety switch going off.when you depress the clutch to start..

For starting some renaults fitted with keycard systems as safety feature..you have to depress the clutch,in which the lcutch pedal switch is depressed this sends info to ecu..the gearbox is in neutral and thus allows the car to start

Hi,so if the neutral safety switch is not turning off, the engine wouldn't start turn over, right?So there are 2 of those safety switches? Clutch and break, right?In neutral position of the gear box, engine starts turning over ether pressing clutch or break.I also take out (this time) ALL 4 spark plugs and tested the sparking. They are firing on all 4 channels.(And again, I smelled the fuel. This time out of the spark plug holes in the head.)Always the first time I try to start the engine it seems as it might start. Almost. It won't.I'm getting closer, that this car drives me crazy somehow.

Well yes..you have to depress the clutch swtich for it to start..tells the ecu the gearbox is in neutral...the other switch is on the break pedal for the ecu and brake lights..

To me going by what your saying now its sounding timing related..maybe its jumped a tooth..do you pocess a compression guage? just to make sure all 4 cylinders have got proper and even psi..if they have your getting spark and fuel..it can only leave timing related problem..if the timing belt hasnt been done for quite sometime its maybe the likely culprit..thats why if you scoped the signal from cam and crank and see if the cam/crank timing has shifted if you dont want to strip the timing cover off and aquire the timing tools to lock the engine

the timing belt needs some care in a close future. Could it probably jump a tooth with a dephase pulley that doesn't work properly? I'll have a look at the valve that controls the dephase pulley. If I fail here, I think it will get expensive.

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